Process for the partial deacylation of poly(n-acyl-alkylenimines)

ABSTRACT

A PROCESS FOR THE PRODUCTION OF PARTIALLY DEACYLATED POLY(N-ACYL-ALKYLENIMINES) WHICH COMPRISES REACTING A POLY(N-ACYL-ALKYLENIMINE) OF THE FORMULA   H-(-(CH2)M-N(-CO-R)-)N-H   WHEREIN M IS 2 OR 3, N IS AN INTEGER OF 1-0-5,000, AND R IS ALKYL OR 1-12 CARBON ATOMS, ARALKYL OF 7-12 CARBON ATOM,S, ARYL OF 8-12 CARBON ATOMS, OR SUBSTITUTED ARYL OF 6-12 CARBON ATOMS, WITH AN ALKANOLAMINE AT A TEMPERATURE OF 150*-250*C., OPTIONALLY IN THE PRESENCE OF AN INERT SOLVENT. DEACYLATION IN THE ABSENCE OF CONCENTRATED MINERAL ACIDS OR INORGANIC SALTS FICILATES RECOVERY OF THE DEACYLATED PRODUCT.

United States Patent 3,833,521 PROCESS FOR THE PARTIAL DEACYLATION OF POLY(N-ACYL-ALKYLENIMINES) Bernhard Karbstein and Gerd Scheppers, Marl, Germany, assignors to Chemische Werke Huls Aktiengesellschaft,

Marl, Germany No Drawing. Filed Oct. 5, 1972, Ser. No. 295,168 Claims priority, application Germany, Oct. 15, 1971, P 21 51 379.1 Int. Cl. C08g 33/08 US. Cl. 260-2 EN 15 Claims ABSTRACT OF THE DISCLOSURE A process for the production of partially deacylated poly(N-acyl-alkylenimines) which comprises reacting a poly (N-acyl-alkylenimine) of the formula wherein m is 2 or 3, n is an integer of -5,000, and R is alkyl of 1-12 carbon atoms, aralkyl of 7-12 carbon atoms, aryl of 8-12 carbon atoms, or substituted aryl of 6-12 carbon atoms, with an alkanolamine at a temperature of 150-250 C., optionally in the presence of an inert solvent. Deacylation in the absence of concentrated mineral acids or inorganic salts facilitates recovery of the deacylated product.

BACKGROUND OF THE INVENTION The present invention relates to a process for the production of partially deacylated poly(N- acyl alkylenimines).

It is known to deacylate poly(N-acetyl-ethylenimine) by refluxing with excess sulfuric acid; see, for example, Iourn. Polymer Sci., Part A, vol. 4, p. 2263 (1966). It is also known from German Unexamined Published Application 1,720,437 to prepare partially deacylated poly (N-acyl-ethylenimines) by reacting poly(N-acyl-ethylenimines) in the liquid phase by heating with an amount of dilute mineral acid required for the desired degree of deacylation, mixing the thus-obtained mineral acid salts of the partially deacylated and/or partially hydrolyzed poly(N-acyl-ethylenimines) with a base, and isolating the free, partially saponified poly(N-acyl-ethylenimines).

One inherent disadvantage in all deacylation methods utilizing mineral acids is that the thus-formed mineral acidsalts must be worked up in a separate, expensive process stage. The use of ion exchangers for this purpose is complicated and costly, due inter alia to complicated solubility conditions. Even when using inexpensive alkali and alkaline earth hydroxides, the workingup procedure is rather expensive, since partially saponified poly(N-acyl-ethylenimines) free of mineral salt can be isolated only from an entirely dewatered and well-filtered reaction solution.

OBJECTS OF THE INVENTION Accordingly, it is a general object of this invention to provide an improved process for the production of partially deacylated poly(N-acyl-alkylenimines) Another object of this invention is to provide a process for the production of partially deacylated poly(N-acy1- alkylenimnes) in the absence of high concentrations of mineral acids or mineral salts.

A further object of this invention is to provide a process for the production of partially deacylated poly(N-acylalkylenimines) wherein the recovery of final product is greatly simplified.

3,833,521 Patented Sept. 3, 1974 Upon further study of the specification and appended claims, further objects and advantages of this invention will become apparent to those skilled in the art.

SUMMARY OF THE INVENTION Briefly, the above and other objects are attained in one aspect of this invention by providing a process for the partial deacylation of poly(N-acyl-alkylenimines) which comprises transamidating a poly(N-acyl-alkylenimine) of the formula um n- The poly(N-acyl-alkylenimines) suitable for the process of this invention can be prepared in a conventional manner by the polymerization of d -oxazolines and/or 4H-5,6-dihydrooxazines using a cationic catalyst, e.g., sulfuric acid or dialkyl sulfates. The value for the degree of polymerization n is Ill-5,000, preferably 300-1,300.

Poly(N-acyl alkylenimines) of the above formula useful in the process of this invention are those wherein acyl indicates a monovalent radical derived from a carboxylic acid or functional derivative thereof, preferably those wherein R is linear or branched saturated aliphatic alkyl, more preferably of 1-12 carbon atoms. Suitable alkyl groups include but are not limited to methyl, ethyl, npropyl, isopropyl, n-butyl, isobutyl, t-butyl, n-undecyl, etc. Also suitable are those compounds wherein R is aralkyl of 7-12 carbon atoms, preferably derived from alkylbenzenes with one or more alkyl groups of 1-6 carbon atoms substituted on the aromatic benzene ring. Suitable aralkyl groups include but are not limited to benzyl, phenethyl, etc. R can also be aryl of 6-12 carbon atoms, preferably phenyl, which furthermore can be substituted by one or more groups on the aromatic ring such as lower-alkyl, e.g., methyl.

The residue R can be identical or different along the polymer chain. Eminently suitable poly(N-acyl-alkylenimines) are poly(N-acetyl-ethylenimines) and poly(N- benzoyl-ethylenimines) Alkanolamines suitable for the transamidation are lower alkanolamines, preferably those of 1-3 carbon atoms in the alkyl group. Suitable alkanolamines include but are not limited to ethanolamine, 1,3-propanolamine and isopropanolamine. Ethanolamine has proved to be particularly advantageous in the process of this invention.

The quantitative ratio of the starting compounds utilized in the process of this invention can be varied to any desired ratio, depending on the desired degree of deacylation. Generally, the poly(N-acyl-alkylenimines) are employed with a molar excess of alkanolamine, based on the acyl groups of the poly(N-acyl-alkylenimines). Preferably, the reaction to obtain 10 to 96% deacylation is conducted with a molar ratio of alkanolamine to acyl groups of the poly(N-acyl-alkylenimines) of 2:1 to 5:1, and especially advantageously with a molar ratio of 3:1.

The process of this invention is generally effected without an inert diluent or solvent. However, it is often advantageous to conduct the transamidation in the presence of an inert solvent, especially when a molar excess of alkanolamine, based on the acyl groups of the poly(N- acyl-alkylenimines), is utilized. While a solvent will generally be used in a 2-5 fold excess based on the poly(N- acyl-alkylenimines), it is also possible to replace the above-mentioned excess portion of the :alkanolamine entirely or partially by a suitable solvent. Suitable transamidation solvents are well-known in the art and include hydration, into A -oxazoline, and the latter can be converted by polymerization into poly(N-acyl-ethylenimines) utilized as the starting material for the process of this invention. The process is thereby rendered particularly economical in this case.

but are not limited to methanol and isopropanol. 5 The products produced according to the present inven- The process of the present invention is carried out at a tion are suitable as auxiliary agents for water treatment, temperature of 150-250 C. Since these temperatures are as well as paper adjuvants and textile softeners (German in most cases above the boiling temperatures of the Unexamined Published Application 2,046,304) or they can alkanolamines and/or of the solvents, the transamidation serve as starting materials for such products. is preferably conducted in an autoclave under internally The examples set forth below serve to explain the procgenerated autogenous pressure. For this purpose, temess of this invention. peratures of 190-220 C. have proved to .be particularly Without further elaboration, it is believed that one advantageous. skilled in the art can, using the preceding description,

The transamidation can be effe ted discontinuously a utilize the present invention to its fullest extent. The folwell as continuously. The degree of deacylation, dependent lowing preferred Specific embodiments h i to on the individual reaction conditions, amounts to maxibe construed as merely'illustratlve, and not llmitatlve of mally 96%. The degree of deacylation obtained with a the remainder of the disclosure in any way whatsoever. given set of reaction conditions can be varied in a re- EXAMPLES producible manner solely by modifying the duration of the reaction and can be determined quantitatively by IR y(N-ace yl-ethylenimine), n about 3000 was adspectroscopy as well as by determining the amount of Ih 1Xed h etheholamlhe heated 2 111 a the N-acyl-alkanolamine formed as a by-product. Under shn'er'eqfllpped a l e havlhg a capaclty m the preferred reaction conditions, i.e., a threefold molar for the hme Pe lmheated helew- The l'eaetlol} 1111K- amount of alkanolamine with respect to the acyl groups 25 ture was then dlssolved an equal amount by Welght of and at 1904200 c in an autoclave, the time required water of a temperature of 70 C., and the resultant mixf 10 to 96% deacylation is houm ture was added dropwise to a tenfold excess of acetone; The partially deacylated poly(N-acyl-alkylenimines) during this step, the deacylation products were precipitated can be isolated by dissolving the reaction mixture in water and Could be separated- (Z-hYdIOXYethYI)eeelamide and precipitating the partially deacylated poly(N-acyl- Was isolated from the liquid phase by distillation, and alkylenimine) with the aid of a known precipitant, e.g., the degree of deacylation was determined from the acetone. However, if more than 30% of the amide groups amount of this compound recovered.

TABLE 1 Degree of deacyl- Poly(N-acetyl- Time Amount of ation Example ethylenimine) Ethanolamine (hr.) amide formed (percent) 1 0.47 mol=40 g--- 1.41 mol=86 g.-- 2 0.175 m01=18. 02 g. 37.2 2 0.47 mol=40 g-.. 1.41 mol=86 g... 3 0.197 mo1=20.3 g 41. 9 3 0.47 mo1=40 g.-- 1.41 m0l=86 g..- 5 0.256 mol=26.4 g- 54. 5 4 0.47 mo1=40 g--- 1.41 mol=86 g... 5 0.344 mo1=35.4 g- 73.2 5 0.47 mol=40 g... 1.41 mol=86 g..-- 6 0.342 mo1=36.2 g. 72.7

have been transamidated. this step is advantageously con- EXAMPLES 6-11 ducted without a precipitant, since the partially deacylated The production of larger amounts (about 1 kg) of poly(N-acyl-alkylemmine) can then be precipitated by partially deacylated poly(N acetyl ethylemmmes), n cooling the aqueous solution to a temperature of 30-10 about 3000 was conduct d 10 t t l C. or less. The preferred method of isolation, however, th e m a 1 er au 0c W e autoclave was equipped with a hydraulic agitator which can be ut1l1zed independently of the degree of conversion Se ante the thusiorm d N 2 nd/Or N 3 h and an electncal heating unit. The amounts of poly(N- d {k b e t ,th h y acetyl: ethylenimine) and ethanolamine employed, the

roxya Ycar OXY am oge F i W1 t e quantifies of acetamide, and the degrees of deacylation,

reacted alkanolamme, from the p ar 1 ly fleacylated as well as the reaction times, are indicated in Table 2.

P y( l y h remalhlhg m the resume under The reaction product was worked up by removing the v m wi h he d f a h n-film e p rg thls thus-formed acetamide and the excess ethanolamine in a technique, the yields of part1ally deacylated poly(N-acylthin-film evaporator at about 200 C./0.3 mm. Hg. The alkylemmmes) range between 90% and 100%. amide was isolated by subsequent redistillation.

TABLE 2 Degree (i Poly(N-acetyleaqy Example ethylenimine) Ethanolamine $1 231 of amide (perg iiig 67 mol=4,100g 1 6.65 l=685 2 67 mol=4,100 g. 3 17.23 mol=1,780 g- 77. 3

11 22.8 mo1=1.900g 67 mo1=4100 I I 9 2114 mol 2:203g::.--.: be

The partially deacylated poly(N-acyl-alkylenimines) produced according to the process of this invention are white to yellowish powders which solidify in the manner of a wax after melting. They are insoluble or exhibit poor solubility in ether, petroleum ether, isopropyl alcohol, dioxane, tetrahydrofuran, benzene, carbon tetrachloride and ethyl acetate. In contrast thereto, they are readily soluble in methanol or chloroform.

The N-Z-hydroxyethyl-carboxylic acid amide isolated as a by-product in the reaction of poly(N-acyl-ethylenimines) EXAMPLES 12-14 Analogously to Examples 1-5, poly(N acetyl-ethylenimine), n about 3000, was reacted with l-amino-3-propanol at 200 C. in a similar agitator-equipped autoclave. The reaction times and the amount of reactants employed are set forth in Table 3. For conducting the working-up operation, the reaction mixtures were in each case distilled in a rotary evaporator where any excess l-aminowith ethanolamine can be converted, e.g., by gas-phase de- 3-propanol and thus-formed N- (S-hydroxypropyl), acetamide were separated in this manner. distillation isolated the amide.

A subsequent rethereof, can make varous changes and modifications of the invention to adapt it to various usages and conditions.

TABLE 3 Degree of deacyl- Poly(N-acety1- l-emino-B- Time Amount of amide ation Example ethylenimine) propanol (hr.) formed (percent) 12 0.4 rnol=34 g 1.2 mo1=90 g 12 0.0588 mol=6.89 g- 14. 7 0.4 mo1=34 g 1.2 mo1=90 g.-. 18 0.0848 mol=9.94 g... 21. 2 14 0.4mol=34 g 1.2 mol=90 g 24 0.1317 mol=15.41 g 32. 9

EXAMPLE What is claimed is:

EXAMPLES 161 8 At a molar ratio of 1:3, poly(N-isovaleryl-ethylenimine) was heated with ethanolamine in a 250 mL-autoclave equipped with an agitator for the time periods indicated to 200 and 220 C., respectively (Table 4). The reaction mixture was worked up analogously to Examples 12-14; It was about 1500.

1. A process for the partial deacylation of poly (N-acylalkylenimines) which comprises transamidating at least 5% of a poly(N-acylalkylenimine) of the formula wherein m is 2 or 3, n is an integer of 10-5,000, and R is alkyl of 1-12 carbon atoms, aralkyl of 7-12 carbon atoms, aryl of 6-12 carbon atoms, or aryl of 6-12 carbon atoms with an alkanolamine at a temperature of 150- 250 C.

2. A process according to Claim 1, wherein m is 2.

3. A process according to Claim 1, wherein the reaction is effected in the absence of an inert diluent.

4. A process according to Claim 1, wherein the poly TABLE 4 Degree of React. deacyl- Poly(N-isovalery1- Time temp. Amount of ation Example ethylenimine) Ethanolamine (hr.) C.) amide formed (percent) 0.4 mol =51 g. =73.4 g 24 200 0.102 mol=l4.79 g. 25. 4 0.4 mo1=51 g =73.4 g.--. 36 200 0.147 mol=2l.3 g 36. 7 0.4 mo1=51 g j 1.2 mol=73.4 g. 24 220 0.314 mol=45.52 g- 78. 5

EXAMPLES 19-24 Further reactions of poly(N acyl-ethylenimines), n

about 2000 to about 4500, with ethanolamine in an agi- (N-acyl-alkylenirnine) is reacted with a molar excess of alkanolamine, based on the acyl groups of the poly(N- acyl-alkylenimine) 5. A process according to Claim 4, wherein the molar ratio of alkanolamine to the acyl groups of the poly(N- acyl-alkylenimines) is 2: 1-5: 1.

TABLE 5 Degree 01' React. deacyl- Time temp. ation Example Poly(N-aeyl-ethylen.imine) Ethenolarnine (hr.) 0.) Amount of amide formed (percent) 19 Poly(N-benzoyl-ethylenirnine) 0.38 mol= 1.14 mol=70 g. 12 200 N gihydroxyethw)benzamide 0.279 mol= 73. 5

g. 20 PolyiN-isobutyrylethylenimine) 0.44 1.33 mo1=81 g-.. 24 220 N-(Z-hyggqxyethyl)isobntyramide 0.022 5 m =5 g. mo g. 21 Poly(Niso-butyryl-ethylen.imine) 0.298 1.49 mol=9l-3 g. 48 220 0.129 m0l=16.9 g 43.3

mol= .8 22 Poly(N-laur%yl-ethylenim.ine) 0.306 mol= 0.917 mol=56.1 g- 24 220 N-(2-hydroxyethyl)lauramide 0.066 mol= 21.6

68.9 g. 23 Poly(lg-p-toluylethylenimine) 0.347 1.04 mol=63.6 g- 24 200 N-(2-ily l o xyethyl)-p-to1nylamide 0.104 30.1

mo1=56 mo g. 24 Poly(N-pli e yl-aeetyl-ethylenimine) 1.09 mol=66.6 g. 24 220 N-(2-hydroxyethyl)phenylacetamide 23. 8

0.363 mol=58.5 g. 0.086 mo1=15.49 g.

EXAMPLE 25 6. A process according to Claim 5, wherein the molar g. (0.453 mol) of a copolymer of methyloxazoline and n-propyloxazoline (molar ratio 1:1, n about 2700) was heated in a agitator equipped 250 mL-autoclave with 83.1 g. (1.36 mol) of ethanolamine for 8 hours to 200 C. The reaction product was worked up analogously to Examples 12-14, isolating 6.88 g. (0.067 mol) of N-(2- hydroxyethyl)acetamide and 8.75 g. (0.067 mol) of N-(2- hydroxyethyl)-butyramide, corresponding to 29.4% deacylation of the copolymer.

The preceding examples can be repeated with similar success by substituting the generically or specifically described reactants and/ or operating conditions of this invention for those used in the preceding examples.

From the foregoing description, one skilled in the art can easily ascertain the essential characteristics of this invention, and without departing from the spirit and scope ratio is 3:1.

7. A process according to Claim 1, wherein the alkanolamine is ethanolamine.

8. A process according to Claim 7, wherein the poly (N-acyl-alkylenimine) is poly(N-acetyl-ethylenimine) or poly(N-benzoyl-ethylenimine) 9. A process according to Claim 8, wherein the poly (N-acyl-alkylenimine) is poly(N-acetyl-ethylenimine).

10. A process according to Claim 9 further comprising isolating N-Z-hydroxyethyl carboxylic acid amide as a reaction byproduct, converting said byproduct to A oxazoline, polymerizing said A -oxazoline to poly(N-acyl-ethylenimine), and using said poly(N-acyl-ethylenimine) as a starting material in the partial deacylation reaction.

11. A process according to Claim 1, wherein the reaction is conducted in an autoclave under autogenous pressure at -220 C.

12. A process according to Claim 1, further comprising recovering partially deacylated po1y(N acyl-alkylenimine) from the resultant reaction mixture by thin-film evaporation.

13. A process according to Claim 1, wherein the reaction is carried out to 10-96% deacylation.

14. A process according to Claim 1, wherein the reaction is etfected in an inert solvent selected from the group consisting of methanol and isopropanol.

15. A process according to Claim 4, wherein the al- 10 kanolamine is ethanolamine, the poly(N-acy1-alkylenimine) is poly(N-acetyl-ethylenimine) or poly(N-benzoylethylenimine), and the reaction is conducted in an autoclave under autogenous pressure at 190220 C.

8 References Cited Homopolymerization of 2-alkyl and 2-aryl-2-oxazolines J. of Polymer Science, part A-l, vol. 4 (196), pp. 2253-2265.

WILBERT J. BRIGGS, SR., Primary Examiner US. Cl. X.R. 

